[linux-dvb] Re: struct dmx_input_t

["Aurelian Pop" <puiu@cs.tut.fi>]

> Aurelian Pop <puiu@cs.tut.fi> wrote:
> >
> > I mean what is the difference if in apps/test/test_dvr.c I change from
> > DMX_IN_FRONTEND to DMX_IN_DVR??? As far as I know, everything behaves the
same.
> > Am I totally in the woods?? :)
>
> When recording, the stream can only come from the frontend, so the
> current implementation ignores the input parameter.
>
> > > The actual implementation is not very intuitive, however. A filter
> > > opened with DMX_IN_FRONTEND *after* the dvr device has been opened
> > > for writing will get the stream from dvr. Why? Just one more bit
> > > of broken dvr device semantics...
> >
> > Please explain what did you mean with "... get the stream from dvr".
>
> The av7110 implementation has actually two demuxes: one in hardware,
> and one in software. When you write to the dvr device, the data goes
> to the software demux, *and* any filters you set (regardless of the
> input paramter) will be set in the software demux. The reason this
> was implemented that way is: DMX_SET_SOURCE was only invented recently
> and is not properly implemented, so it was assumed to "be the right
> thing". That way you can e.g. replay a TS with test_dvr_play and
> analyze the stream withn scan, without having to change the filter
> settings in scan.c.
>
> In the current implementation it's best to use the dvr device for
> TS recording and simple playback only, and keep the fingers off it
> otherwise.
> The "V4" version of the DVB API will attempt to clean this up.
>
>

Thanks! Now it's clear for me! ;)

Aurelian



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